It is known that for carrying out the vulcanization of tires, presses are used generally comprising a bed housing the lower portion (holder) of one or more (generally two) vulcanization molds, in which the tire to be vulcanized is introduced. After the correct positioning of the tire has taken place, a movable crosspiece kinematically connected to the bed by a connecting rod-crank assembly is lowered onto the bed; fastened under said crosspiece is a number of upper counter-molds corresponding to that of the lower holders and designed to be paired therewith thereby forcing each tire to take a given conformation in the progress of the vulcanization process. In greater detail, within the tire enclosed between the lower holder and upper counter-mold is a chamber or bladder made of elastomeric material inflatable with steam under pressure, which bladder urges the tire against the mold walls. At the same time the steam contained in the bladder together with that circulating through the different parts of the mold and close thereto transmits the necessary heat for carrying out vulcanization of the tire.
When the above process is over, the crosspiece or beam and the upper counter-mold or counter-molds together with it are raised from the bed and optionally moved sideways relative thereto, to enable the vulcanized tires to be unloaded and a new tire ready for vulcanization to be introduced into each lower holder.